CN112010758A

CN112010758A - Triethylamine recovery method

Info

Publication number: CN112010758A
Application number: CN202011027260.XA
Authority: CN
Inventors: 孙彩军; 沈孝峰; 侯方方
Original assignee: Anhui Jinhe Industrial Co Ltd
Current assignee: Anhui Jinhe Industrial Co Ltd
Priority date: 2020-09-26
Filing date: 2020-09-26
Publication date: 2020-12-01

Abstract

The invention relates to a triethylamine recovery method, which comprises the following steps: 1) adding 2000 kg of ammonium bicarbonate and 3 parts of water into a reaction kettle, and stirring to mix into suspension; 2) then adding waste acid containing triethylamine salt dilute sulfuric acid in the former working section of 6500 and 7500 liters; 3) after the reaction of the stirred materials is finished, measuring the pH value of the materials in the reaction kettle to be between 3 and 4.5; 4) adding liquid ammonia into the reaction kettle, and reacting for 30 minutes when the pH value of the materials in the kettle is between 10 and 12; 5) heating the materials in the reaction kettle to 90-100 ℃ by steam, allowing excessive ammonia and triethylamine in the kettle to escape together in an alkaline environment, and recovering crude triethylamine through condensation; 6) and (3) rectifying the triethylamine crude product at 85-95 ℃ and drying by KOH to obtain the finished product triethylamine. The invention has the advantages that: simple production steps, improved recovery efficiency, energy conservation and reduced environmental pollution.

Description

Triethylamine recovery method

The technical field is as follows:

the invention relates to a triethylamine recovery method.

Background art:

according to the traditional triethylamine recovery process containing waste acid, after most of dilute sulfuric acid in the waste acid is reacted by calcium carbonate, calcium hydroxide is added into an alkali precipitation kettle, triethylamine is precipitated in an alkaline environment after heating, a crude product is cooled, and sulfuric acid is added into the kettle and adjusted back to be neutral. The production process is shown in figure 1, because the production is intermittent, stone powder and lime are dissolved, waste acid is dripped, lime water is dripped, adjustment is carried out, calcium sulfate centrifugation and other steps are carried out, the operation is complex, dust such as lime, stone powder and the like greatly causes great occupational disease influence on human bodies, the steam consumption is high, the triethylamine recovery rate is low, the utilization rate of solid waste calcium sulfate is low, the salt content such as calcium sulfate and the like in waste water is large, and the pollutant treatment is difficult.

The reaction principle is as follows: (NH)₄)₂CO₃+H₂SO₄==(NH₄)₂SO₄+CO₂↑+H₂O

NH₃.H₂O+H+=NH₄++H₂O。

The invention content is as follows:

the invention aims to overcome the defects of complex process, high cost, difficult pollutant treatment and low recovery rate in the prior art, and provides a triethylamine recovery method.

In order to achieve the purpose, the invention adopts the following technical scheme:

a triethylamine recovery method is characterized by comprising the following steps:

1) adding 2000 kg of ammonium bicarbonate and 3 parts of water into a batching kettle, stirring and mixing to form suspension, and then feeding the suspension into a reaction kettle;

2) pumping waste acid containing triethylamine salt dilute sulfuric acid in a front working section of 6500 and 7500 liters into a reaction kettle at the flow rate of 50L-100L/min;

3) when the waste acid is completely pumped, stirring for 30 minutes to fully react, and after the reaction is finished, measuring the pH value of the material in the reaction kettle to be 3-4.5;

4) slowly dripping liquid ammonia into the reaction kettle, finishing dripping when the pH value of materials in the kettle is between 10 and 12, and naturally reacting for 30 minutes;

5) heating the materials in the reaction kettle by steam, ensuring that the materials in the reaction kettle are 90-100 ℃, allowing excessive ammonia and triethylamine in the reaction kettle to escape together in an alkaline environment, and recovering a crude triethylamine product by condensation;

6) the triethylamine crude product is rectified at 85-95 ℃ to remove most of water, and is dried by KOH to obtain a finished product of triethylamine for the previous working section.

7) And pumping the materials in the reaction kettle to MVR for concentration to obtain the finished product of ammonium sulfate.

On the basis of the technical scheme, the following further technical scheme is provided:

the water added into the batching kettle in the step 1) adopts the MVR concentrated wastewater recovered in the step 7).

In the step 5), materials in the reaction kettle are heated by steam, the materials in the reaction kettle are ensured to be 90-100 ℃, excessive ammonia and triethylamine in the reaction kettle escape together in an alkaline environment, after crude triethylamine is recovered by condensation, ammonia gas and a small amount of triethylamine which cannot be condensed are washed by dilute acid from a previous working section and are recovered and reused.

The invention has the advantages that:

1. the process technology adopted by the project is advanced, mature and reliable; the method has the advantages of simple steps, reduced repeated operation, reduced operation complexity and energy conservation.

2. Compared with the original traditional production process, the production steps are reduced, the crystallization production efficiency is improved, the steam consumption is reduced, the environmental pollution is reduced, the power consumption is reduced, and the steam is saved by 30T/day through long-term operation and calculation; the whole recovery cost is reduced

3. The process has the advantages of simple and smooth process and low investment. Secondly, the production efficiency is greatly improved. The production process is shortened, personnel are reduced, (12 persons/4 shifts originally, 8 persons/4 shifts now), and the reaction efficiency of the whole production flow is optimized;

4. the production field greatly improves the environment, reduces dust, reduces solid waste and pollution, the value of the prior calcium sulfate is 8000T, and the prior ammonium sulfate can be used as fertilizer and the like to create a certain value.

Description of the drawings:

FIG. 1 is a flow chart of a neutralization section in the existing acesulfame potassium production process;

FIG. 2 is a flow chart of the neutralization section in the acesulfame potassium production process of the present invention.

The specific implementation mode is as follows:

the triethylamine recovery method provided by the invention, as shown in figure 2, comprises the following steps:

1) public engineering facilities such as water, electricity, gas and the like are checked, and safety is guaranteed;

2) opening an emptying reaction kettle, adding 2000 kg of ammonium carbonate and 3-square water or recovered wastewater (MVR concentrated solution) into the kettle, stirring and mixing for 15min, and forming a suspension from materials in the kettle;

3) closing the reaction kettle, emptying, opening a large distillation valve, then opening a waste acid (dilute sulfuric acid containing triethylamine salt in the front section) metering tank pump, pumping 6500-7500 liters of waste acid into the reaction kettle according to a certain flow (50L-100L/min) (the flow can be adjusted according to the distillation speed), and determining the pH value or the concentration content of the waste acid;

4) when the waste acid is completely pumped, stirring for 30 minutes to ensure that the waste acid and ammonium bicarbonate are fully reacted, generating ammonium sulfate and free triethylamine after the reaction is finished, and determining the PH value of the material in the reaction kettle to be between 3 and 4.5;

5) opening a liquid ammonia valve, slowly dripping liquid ammonia into the kettle (a liquid ammonia dripping pipe extends into the bottom of the kettle), stopping dripping when the pH value of materials in the kettle is between 10 and 12, neutralizing excessive dilute sulfuric acid, keeping alkalinity, and naturally reacting for 30 minutes;

6) opening a steam valve, heating materials in the kettle, ensuring that the materials in the kettle are 90-100 ℃, allowing excessive ammonia and triethylamine in the kettle to escape together in an alkaline environment, recovering crude triethylamine through condensation, and washing ammonia gas and a small amount of triethylamine which cannot be condensed through dilute acid from a previous working section for recycling;

7) rectifying the crude triethylamine product at 85-95 ℃ to remove most of water, and drying by KOH to obtain a finished product triethylamine product for use in the previous working section;

8) and pumping the materials in the kettle to MVR for concentration to obtain the finished product of ammonium sulfate.

Claims

1. A triethylamine recovery method is characterized by comprising the following steps:

5) heating the materials in the reaction kettle by steam, ensuring that the materials in the reaction kettle are at 90-100 ℃, allowing excessive ammonia and triethylamine in the reaction kettle to escape together in an alkaline environment, and recovering crude triethylamine through condensation;

6) rectifying the recovered triethylamine crude product at 85-95 ℃ to remove most of water, and drying by KOH to obtain a finished product triethylamine for a front working section;

2. The triethylamine recovery method according to claim 1, wherein:

3. The triethylamine recovery method according to claim 1, wherein: the water added into the batching kettle in the step 1) adopts the MVR concentrated wastewater recovered in the step 7).